The present invention relates to a multiroom air-conditioning apparatus having an outdoor side unit and a plurality of room units and adapted to simultaneously cool or heat all of a plurality of rooms, and simultaneously cool one room and heat the other.
The multiroom air-conditioning apparatus capable of simultaneously cooling one of a plurality of rooms and heating the others are proposed in Japanese Pat. Publication Nos. 52-24710/1977, 52-24711/1977 and 52-27459/1977 and Japanese Utility Model Publication No. 54-3020/1979.
In the multiroom air-conditioning apparatus disclosed in the above Japanese Pat. Publication Nos. 52-24710/1977 and 52-24711/1977, four-way change-over valves and outdoor heat exchangers the numbers of which are in agreement with that of outdoor side units are required. Consequently the construction of the pipe circuits becomes complicated, and the manufacturing cost increases. Since it is necessary that, with respect to each room unit, two inter-unit pipes be drawn out from the outdoor side unit, two inter-unit pipes be drawn out from the outdoor side unit, the number of the inter-unit pipes increases, and the piping becomes troublesome. Moreover, during a room cooling and heating operation in which one of a plurality of rooms is cooled with the others heated simultaneously, the outdoor heat exchangers corresponding to the room units function as condensers and evaporators to discard the heat to the outside, which heat cannot be recovered.
In the multiroom air-conditioning apparatus disclosed in the above Japanese Utility Model Publication No. 52-27459/1977, a combination of a coolable room and heatable room in a room cooling and heating operation, in which one of a plurality of rooms is cooled with the others heated simultaneously, is determined in advance, and the room cooling and heating operations cannot be selectively carried out in each room. Namely, these air-conditioning apparatus cannot be conveniently used.